Can we have a separate approval workflow for Contingent Worker Expense Report?

Summary:

Hi Members,

We have a requirement to reject all the expense report submitted by the contingent workers. They should only submit expense report for others but should not submit for themselves. We tried to create a BPM rule for contingent workers but not able to find a condition which will select only those expense report submitted by contingent workers. Can you help us if any condition is available to configure separate rules for contingent workers?

Incase we do not such condition is there a way to have approval rules based on list of users? Like we can create a list of users if we configure BPM rules in spreadsheet?